Pin type contact member



F. REUTTER PiN TYPE CONTACT MEMBERS Original Filed Jan. 17, 1951 llHIHILI ORNEYS,

Patented June 20, 1933 UNITED STATES PATENT, OFFICE FREDERICK REUTTER,OF .WATER-BURY, CCNNECTICUT, ASSIGNCR T SCOVILL MANU- FACTURING COMPANY,OF WATER-BURY, CONNECTICUT, A CORPORATION OF CON- N ECTICUT I PIN TYPECONTACT MEMBER Original application filed January 17, 1931, Serial No.509,291. Divided andthis application filed March 5, 1932. Serial No.597,026.

This invention relates to pin type contact members such as are employed,for example, in radio tube bases and other electrical devices havingplug-in connections, and this application is a division of myco-pending.

application Serial Number 509,291, filed J anuary 17, 1931.

' Devices of this type include a base mem-- her or a disc of insulatingmaterial, such as porcelain, bakelite, glass or some similar substance,having a number of holes extending therethrough for receiving the usualcontact pins. In one well-known way of making such devices, each hollowpin is provided with an outer shoulder spaced somewhat from one end ofthe pin with the surface between the shoulder and adjacent end knurledor otherwise roughened to hold the pins against turning when such end ispositioned in a-pin receiving hole in the base. After being pushed 1ntoplace, the end of the pin is spun over to engage the side of the baseopposite to that engaged by the shoulder so as to hold the pin in theopening. Contact members made in this way have not been entirelysatisfactory. The holes in the base. members vary considgably in size sothat the pins are fre- ./'quen tly loose, while the discs themselvesvary in thickness to such an extent that tools cannot fully compensatefor the different sizes. At the same time, the individual pins in afinished base frequently extend outwardly for varying distances.

An object of this invention is to provide a contact base of the type setforth constructed and arranged so that the pins are rigidly associatedwith the base member and extend outwardly from the base member apredetermined and equal amount irrespective of manufacturinginaccuracies in the size of the openings or iii the original lengths ofthe pins.

This and other objects which will be apparent to those skilled in thisparticular art are accomplished by means of the invention illustrated inthe accompanying drawing is which,

Fig. l is a sectional view-of one type of finished article employing acontact base embodying the present invention.

In making the contact members of the present invention, a base member ordisc 5 of any suitable insulating material having the desired number ofpin receiving holes 6 is provided. Each contact pin 7 is hollow and isoriginally formed of a diameter which permits it to be positioned freelyin an associated hole, a fiange 8 being formed on the inner end toengage the inner face of the base member 5. Each pin 7 is of such lengthwhen first positioned in the base as to extend out- "wardlyfrom the basea greater distance than is desired in the finished product. In otherwords, each pin is provided with an excess of metal to permit asubsequent forging operation which expands that portion lying withintheopening 6' so as to force it outwardly into binding engagement withthe wall of the opening. This forging operation simultane- ,ouslyshortens the pin to the point where it extends the desired distancebeyond the base member 5. The excess metal in the pin is employed in theforging operation to form a head or collar 9 which engages the basemember 5 on the side opposite from the flange or collar 8 and whichco-operates in rigidly securing the pin in place.

One form of apparatus for manufacturing the contact base of the resentinvention is illustrated in Figs. 3 an 4 and consists of a supportingbed 10 on which the disc or base member 5 with the freely assembled pins7 is positioned, a pin supporting mandrel 11 being securely positionedin. the bed so as to extend into the .interior of each hollow pin 7. Aco-operating plunger 12 having a bore 13 which is enlarged at its lowerend to form a recess 14 for receiving the upper: portion of ingoperation. The mandrel 15 is'movable relatively to the plunger 12 and isnormally forced downwardly by a suitable spring 16 engaging the mandrelhead 17 located in a spring chamber 18.

Each pan 7 is originally formed of such length that when positioned inthe base member 5 it projects outwardly therefrom a greater distancethan is desired in the finished article. The base member is supported onthe bed and the stationary mandrel 11 projects upwardly into the pin 7.The plunger .accuracies, origmal hollow It will, of course,

12 is lowered and the outer portion of the pin 7 is received in therecess 14 between the wall thereof and the movable mandrel 15. It willbe apparent that downward movement of the plunger 12 forges the metal ofthe pin 7 that is within the opening 6 to expand outwardly and engagethe wall of the opening with a firm grip, and produces a thie (ening ofthe pin wall within the opening to provide a rugged construction, thedegree of thickening being determined by the space between the mandrel11 and the wall of opening 6. Downward movement of the plunger 12 iscontinued until the outer end of the pin 7 is positioned exactly theright distance away from the disc 5. The flow of excess metal occasionedby this continued movement provides a bead 9 which engages the outerface of the base member 5 and assists in rigidly securing the pin 7 inplace. The inner wall of the pin is supported by the co-operating'mandrels'll and 15, the latter being forced upwardly into the plunger bythe stationary mandrel 11 as the plunger moves down.

It will be apparent that manufacturing inboth in the dimensions of thepin 7 and in the size of openings 6 in the base member, areautomatically compensated for when the pins are secured in place in themanner described. It a greater expansion of the pin 7 to engage the wallof the opening 6 than is shown in the drawing is required, then the bead9 will be slightly smaller, and vice versa. At the same time, absolutelyequal projection of all pins 7 from a given base member or disc 5 isassured, ir-.

respective of manufacturing inaccuracies or slight differences in lengthof the original pins 7, as the extent of projection is positivelydetermined by the position of the plunger 12 at the finish of itsdownward stroke. Differences of length of the different original pinswill merely cause slight differences in the sizes of the beads 9 in thefinished article. be understood that the plunger 12- has a suflieientnumber of recesses 14 and associated mandrels 15 to simultaneously forgeall pins in a given base.

Fig. 1 shows one form of finished article in which the side wall 20 hasbeen mounted on the base member or disc 5 in the usual way to provide atube base. However, it will be apparent that the present inventionisapplicable to all other forms of contact members of the plug-in type aswell as the particular form illustrated.

I claim:

1. The combination in a contact member of a base, a contact pinextending through and beyond an opening in said base and projectingbeyond one side of said base a predetermined extent and having thatportion of its length whichis located within said opening of greaterthickness than the projecting portion and engaging the wall of saidopening with a binding grip.

2. The combination in a contact member of abase, a contact pin extendingthrough and beyond an opening in said base and projecting beyond oneside of said base a predetermined extent and having that portion of itslength which is located'within said opening of greater thickness thanthe projecting portion and engaging the wall of said opening with abinding grip, and base-engaging flanges at each end of said thickenedportion. In testimony whereof, I have signed my name to thisspecification this third day of March, 1932.

FREDERICK REUTTER.

